After his resignation, a live microphone David Cameron was wearing caught him in an unguarded musical moment

Published July 11, 2016•Updated on July 11, 2016 at 7:24 pm

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David Cameron has gone out not with a bang, nor a whimper, but a mystery tune.

Seconds after the British prime minister finished telling reporters of his intention to step down from office this week, he walked back through the door of his Downing Street residence — and the live microphone he was still wearing caught him in an unguarded musical moment.

"Do doooooooo, do doooo," he sang to himself, according to the clip sent by BBC reporter Daniel Sandford.

It wasn't immediately clear what tune Cameron was singing, but the social media world poured forth with often-satirical suggestions. One writer opined that Cameron had just unwittingly revealed the secret "Open Sesame" musical code for the Downing Street door. Another theorized that it was Cameron's personal "game over" videogame hook. Some thought they detected a hint of "The West Wing" theme tune.

Soon, hastily remastered clips of Cameron's doings accompanied to the beats of Dr. Dre were doing the social media rounds.

Cameron said Monday he will step down in two days in favor of Theresa May, a senior member of his Cabinet who will become Britain's second female Prime Minister. May's main rival for prime minister stepped down at noon Monday, making May leader-in-waiting.

Cameron had announced his resignation last month because he backed the losing side in a referendum for Britain to leave the European Union. So did May — but infighting, bad timing and cold feet among leaders of the victorious "leave" campaign means that she will have the task of leading a divided country out of the EU.